Knife sharpener



FIG. 1 is a top, from and left side perspective view of a knife sharpener showing our new design in the open position;

FIG. 2 is a top, rear and right side perspective view thereof;

FIG. 3 is a front elevation view thereof;

FIG. 4 is a rear elevation view thereof;

FIG. 5 is a right side elevation view, the left side elevation being a mirror image thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a top, front and left side perspective view of a knife sharpener showing our new design in the closed position;

FIG. 9 is a top, rear and right side perspective view thereof;

FIG. 10 is a front elevation view thereof;

FIG. 11 is a rear elevation view thereof; and,

FIG. 12 is a right side elevation view, the left side elevation being a mirror image thereof.

The broken lines in the drawings are directed to portions of the knife sharpener that form no part of the claim. 

CLAIM The ornamental design for a knife sharpener, as shown and described. 